Panel bend



Aug- 19, l941- E. E. M Exmm-:Ry 2,253,219

' i PANEL BEND' Filed Feb. 16, V19:59

l .arngya Patented Aug. 19, 1941 UNITED STATES PATENT OFFICE Application February 16, 1939, Serial No. 256,654 s Claims. (Cl. 1411-309) `This invention relates to the formation of a bend in a veneer panel and has for a primary object the employment of `a structure as a method of forming the structure into a bend that will give a smooth curve and be suiliciently strong that ,outside posts or other supporting elements may be dispensed with. It is a further important object of the invention to form a bend that will be exceedingly simple in structure and that will permit production without intricate machines or steps so that the'cost of production may be relatively low.

These and other objects `andadvantages of the invention will become apparent to those versed in the art from the following description lof one particular form as illustrated moreV or less diagrammatically in the accompanying drawing, in which Fig. 1 is a view in sideelevation of the various parts in disassembled relation required to form the bend;

Fig. 2, an edge elevation in assembled relation;

Fig. 3, a plan view with the inner .back and cross bands broken away; and

Fig. 4, an end elevation of the completed bend. l Like charactersof reference indicate like parts throughout the various views in the drawing.

A core I is initially built up from any suitable material following the usual procedure wellknown to those versedin the art. The core as a rule is generally built up from a number of pieces of wood glued together to form a core of the desired approximate thickness. The core I0 is cut away and a core insert II, made out of suitable wood, is inserted and gluedflnto place.

This core insert II has a thickness less than thatV of the core IU and is backed up by a spline of wood I2 or other suitable resilient material such as fabric, rubber, and the like, to bring the com.- bined thickness of the insert II and the spline I2 to equal the thickness of the core I0.` A face cross band I3 is glued to the core I 0 and the outer side of the spline I 2., the insert IIbeing glued by its ends and its outer face respectively to the abutting ends oi" the core I0 and the inner face of the spline I2. Thefcross band I3 is then covered by a face ply or band It to give the vdesired external nish face.

After thesevarious members are thus assembled the insert II is cut across the area to be bent by a plurality of relatively closely spaced slots I5. I'he transverse slots I5 may, of course,

be cut prior to the application of the cross band I3 .and the face band I4, the exact sequence of4 these steps being immaterial and subject to the practice within the local shop.

After the insert II has been slotted, a back cross band I6 has an adhesive applied over its area to contact the core I0 up to some such zone B, Fig, 4, but the adhesive is omitted over the remaining area of. the band lI6 which will be over the slotted portion of the insert II. The back cross band I6 having the adhesive thus applied is placed over the core to carry this cross band I6 from one part of the core I0 across the insert II, to have the adhesive secure the cross bandf I6 to the core I0 to one side of the insertY II but leaving the cross band I6 entirely free from adhesion to the insert II `particularly over that area thereof which carries the slots lli.` Then the back faceband Il is placedover the cross band I6 and secured thereto by any suitable adhesive. The panel thus formed is takento the bending machine, glue or adhesive is sprayed under the cross band I6 by liftingit up as indicated in Fig. 2; the band `I6 and its adhering bandV I 'l dropped down onto theinsert II; and the panel then is bent in the usual manner before the glue sets to assume that form as indicated in Fig. 4 or any other degree of curvature as may be desired. The underfolded section I6 is less in length than the top section Il, and has a length substantially equal to one-half of the length of the slotted area of the core Ill. Reierring to Fig. 4, it will be noted that the segments of the insert II between adjacent slots I5 come together by their inner ends and the cross band I6 fits' nugly across and against their faces.

In the bending operation, the resilient` spline I2 supports theV individual segments between slots I5 of the insert II, and,` being of a resiliently yielding nature, permits the corners of thosesegments adjacent the spline to press into the spline while the outer cross band I3 and face band I4` bend around in a uniform curve without the lines of those segment `corners defining transverse lineson the face band I4.' Also, as the bend is formed, the back band `I'I with its. cross band I6, being initially free and lubricated with the freshly applied adhesive, travel relatively longitudinally around-over the insert II to have their i ends shift a distance such as from A to C, Fig. 4,

these points, of course, being varied depending upon the lengths of those bands as originally employed.

Then, after the bending has taken place, the bend is held under pressure until the adhesive sets between the face band I1 and the back rband I6 and between the back band I6 and the insert Il and core I over which it laps. The band I6 then adheres intimately over the back faces of the insert segments, the remainder of the insert I I, and the lapped over part of the core II). The back band I'I, in the finished bend will present a smoothly curving surface without any apparent bend lines, the width of the segments of the insert II between slots I5 being relatively small.

Referring to the back cross band I6 in its initial state before having adhesive applied to it, and before being placed over and on the core I6, this cross band I6 is cut through along the line D-D and then rejoined by means of a narrow band of paper I8 (any flexible, thin fabric will do) adhesively lapped over marginal portions of the band I6 adjacent the line D-D. This paper I8 forms a hinge, and the outer portion of the band (left-hand side in Fig. 2) is swung around and against the under or inner face of the band I6. With this band I5 thus folded, adhesive is applied over the under face of the band and over the folded section, thereby causing that part of the under face of the band IB covered over by the folded over section to be left free of adhesive, and also causing the then inner face of that folded section to be left free of adhesive. Then the folded section of the band is unfolded to swing it around into its original plane with the major part of the band I6. There willthen be an area of adhesive on the top or outer side of that unfolded section which will contact the inner face of the band I'I when it is applied thereunder. The primary purpose of initially folding under that section of the band I6 is to keep adhesive off of that area of the band I6 which is to extend across the core insert II, while the band I6 is first b'ing applied to the core I0. After the band I6 has received its under face adhesive coating and the underfolded section straightened out, the band I6 is placed over the core I0, to have its under adhesive side placed to one side of the insert II as heretofore indicated, to have the uncoated area extend on over the insert I I. Then the back cross band I'I, suitably coated by adhesive over its entire inner face, is placed adhesive face down on the band I6 and pressed thereagainst. That area of the unfolded section of the band I6 which was originally coated by adhesive when folded under the band I6, of course presents that same adhesive coated area on the outer or upper side when the section is unfolded, to have that area contact with the adhesive' coated face of the band I'I-both bands I6 and II thus being each initially coated over that folding section area. The sole purposes of the initial folding under of the 'end portion of the band I6 are to prevent initial coating of the fold inclosed area and to permit the band to receive its adhesive easily by passingy it in folded condition straight through a glue applying machine.

While I have herein shown and described my invention in the one best form as now known to me, it is obvious that structural changes may be employed, such for example as employing V-slots in place of the rectilinear slots I5, without departing from the spirit of the invention, and I,

therefore, do not intend to be limited to that precise form beyond the limitations that may be imposed by the following claims.

I claim:

1. For a ply-wood bend, a panel having a core, comprising an insert in the core, and a spline across and adhering to the insert, said spline having a greater degree of resiliency than that of said insert, a band adhering to said spline, said insert being provided with a plurality of transverse, spaced slots entering the insert from its side opposite the spline side, and a back band adhering to said core on its face removed from said first band and to one side of said insert and extending therefrom loosely across at least the slotted area of said insert, whereby the loose portion of the back band may receive adhesive and be free to travel longitudinally relatively over the insert when the bend is formed, said back band being in two parts divided within the length of the slotted area of the insert, and a length of thin flexible material hinging the divided parts of the back band together.

2. For a ply-wood bend, a panel having a core, the core in a bending zone of the panel being reduced in thickness, a spline joined with the core to extend at least across said reduced thickness portion, .said portion having relatively closely spaced slots extending thereacross opening on' the opposite side from the spline, a face band adhesively secured over said core and spline, a back band adhesively joined to said core and having an end portion extending from the joined portion looseli7 Over `said slotted area of the core said back band being in two parts divided within the length of the slotted area of the insert, and a length of thin flexible material hinging the divided parts of the back band together.

3. That method of forming plywood for a bend which comprises forming a plurality of slots across a core parallel to the axis of curvature of the intended bend, hinging one section to another of a band by a thin flexible sheet of material, folding one band section back under the other, the underfolded. section being less in length than the top section, applying an adhesive over the underside of the folded section and also a portion of the underside of the top section whereby the areas of the underside of the top section covered over by the folded section and of the then innerside of the folded section are left free of adhesive, the said underfolded section having a length substantially equal to one-half of the length of the slotted area of said core, unfolding said underfolded section to swing its adhesive coated side around to be then on its top side, placing said unfolded band with its under adhesive coated area onsaid core to one side of the core slotted area to have the uncoated underside areas of said band sections extend over said core slotted area, and placing a second band over the first band with an adhesive applied over the area therebetween to have the second band overlap said hinge material and to have the second and first bands become adhesively secured one to the other.

' ELMO E. ALEXANDER. 

